Faraday's Law MCQ Quiz in বাংলা - Objective Question with Answer for Faraday's Law - বিনামূল্যে ডাউনলোড করুন [PDF]
Last updated on Mar 24, 2025
Latest Faraday's Law MCQ Objective Questions
Top Faraday's Law MCQ Objective Questions
Faraday's Law Question 1:
How many laws are there in Faraday's laws of electro-magnetic Induction?
Answer (Detailed Solution Below)
Faraday's Law Question 1 Detailed Solution
Faraday’s first law of electromagnetic induction states that whenever a conductor is placed in a varying magnetic field, emf is induced which is called induced emf. If the conductor circuit is closed, the current will also circulate through the circuit and this current is called induced current.
Faraday's second law of electromagnetic induction states that the magnitude of emf induced in the coil is equal to the rate of change of flux that linkages with the coil. The flux linkage of the coil is the product of number of turns in the coil and flux associated with the coil.
\(E = - N\frac{{d\phi }}{{dt}}\)
Faraday's Law Question 2:
All induction type transducers are based on
Answer (Detailed Solution Below)
Faraday's Law Question 2 Detailed Solution
Inductive transducers:
These works on the principle of change in inductance due to the quantity that is to be measured. These are basically two types.
- Self-generating
- Passive
They are based on Faraday's law.
Example: LVDT (Linear Variable Differential Transformer)
It measures the displacement in terms of the voltage difference between its two secondary voltages.
Faraday's law
It describes that the current will be induced in a conductor which is exposed to a change in a magnetic field. The direction of the current is given by Lenz's law.
Induced emf is given by:
\(e = -N \frac{d\phi}{dt}\)
Important Points
Seebeck effect: It is a phenomenon where the temperature difference between the two dissimilar electrical conductors produces a voltage. When the heat is applied to one conductor then the heated electrons flow from that to the other conductor.
Peltier effect: It is the reverse phenomenon of the Seebeck effect. The electrical current flowing through the junction connecting two materials will emit or absorb the heat per unit time at the junction to balance the difference in the chemical potential difference.
Faraday's Law Question 3:
A quantitative relation between induced emf and rate of change of flux linkage is known as
Answer (Detailed Solution Below)
Faraday's Law Question 3 Detailed Solution
Faraday's laws: Faraday performed many experiments and gives some law about electromagnetism.
Faraday's First Law: Whenever a conductor is placed in a varying magnetic field an EMF gets induced across the conductor (called as induced emf), and if the conductor is a closed circuit then induced current flows through it.
A magnetic field can be varied by various methods –
- By moving magnet
- By moving the coil
- By rotating the coil relative to a magnetic field
Faraday's second law of electromagnetic induction states that the magnitude of induced emf is equal to the rate of change of flux linkages with the coil.
- According to Faraday's law of electromagnetic induction, the rate of change of flux linkages is equal to the induced emf
- \(E=N\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right){\rm{Volts}}\)
Where
E = Induced emf
N = Number of turns
\(\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right)\) = Rate of change in flux
Flux linkage:
ψ = N × ϕ
\(E= N\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
\(E = \left( {\frac{{{\rm{d\Phi N }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
\(E=\left( {\frac{{{\rm{d\psi }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
Faraday’s law of electromagnetic induction, the rate of change of flux linkage is equal to induced emf.
Faraday's Law Question 4:
In the table shown, List I and List II, respectively, contain terms appearing on the left-hand side and the right-hand side of Maxwell’s equations (in their standard form). Match the left-hand side with the corresponding right-hand side.
|
List I |
List II |
||
|
1. |
∇. D |
P |
0 |
|
2. |
∇ × E |
Q |
\(\rho_v\) |
|
3. |
∇. B |
R |
\( - \frac{{\partial B}}{{\partial t}}\) |
|
4. |
∇ × H |
S |
\(J+ \frac{{\partial D}}{{\partial t}}\) |
Answer (Detailed Solution Below)
Faraday's Law Question 4 Detailed Solution
Various Maxwell laws are shown in the table
|
Differential form |
Integral form |
|
1. \(\nabla .\vec D = \rho_v\) |
\(\oint \vec D.\vec ds = \mathop \smallint \limits_v^{} \rho_vdV\) |
|
2. \(\nabla \times E = - \frac{{\partial B}}{{\partial t}}\) |
\(\mathop \oint \limits_L^{} \vec E.\overrightarrow {dl} = \frac{{ - \partial }}{{dt}}\;\mathop \smallint \limits_s^{} \vec B.\overrightarrow {ds}\) |
|
3. \(\nabla .\vec B = 0\) |
\(\oint \vec B.\overrightarrow {ds} = 0\) |
|
4. \(\nabla \times H =J+ \frac{{\partial D}}{{\partial t}}\) |
\(\oint \vec H.\overrightarrow {dl} = \mathop \smallint \limits_s^{} \left( {\vec J + \frac{{d\vec D}}{{dt}}} \right)ds\) |
Faraday's Law Question 5:
If a copper conductor is moved across a magnetic field -
Answer (Detailed Solution Below)
Faraday's Law Question 5 Detailed Solution
When a copper conductor is moved across a magnetic field, an emf or voltage is induced in the wire.
Principle of Generation of EMF:
Faraday's Law of Electromagnetic Induction states that whenever there is a relative motion between a conductor and magnetic field, an emf will be induced.
EMF can be induced in two ways:
- Statically Induced EMF: When the conductor is stationary and the magnetic field is changing, the induced EMF is known as statically induced EMF. Example- Transformer
- Dynamically Induced EMF: When the conductor is moving and the magnetic field is stationary, the induced EMF is known as dynamically induced EMF. Example- Generator
Faraday's Law Question 6:
The line integral of the vector potential A around the boundary of a surface S represents
Answer (Detailed Solution Below)
Faraday's Law Question 6 Detailed Solution
Using stroke’s theorem
\(\oint \vec A.\overrightarrow {dl} = \mathop \smallint \limits_S^\; \left( {\nabla \times \vec A} \right).\overrightarrow {ds} \)
∵ \(\vec A\) is vector magnetic potential
∵ ∇ × A = Curl \(\left( {\vec A} \right)\) = Magnetic Flux density \(\vec B\)
\(\Rightarrow \;\mathop \smallint \limits_S^\; \left( {\nabla \times \vec A} \right).ds = \mathop \smallint \limits_S^\; \vec B.\overrightarrow {ds} \) = Flux through the surface S
Faraday's Law Question 7:
Which of the following options form the basis of the production of electrical power using DC generation?
Answer (Detailed Solution Below)
Faraday's Law Question 7 Detailed Solution
The production of electrical power using DC generation based on the principle of Faraday's first law of electromagnetic induction i.e. when the magnetic flux linking a conductor changes, an EMF is induced in the conductor.
Faraday’s First Law of Electromagnetic Induction:
- It states that, "whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. If the conductor circuit is closed, a current is induced, which is called induced current".
- The magnetic field intensity in a closed loop can be changed
- By rotating the coil relative to the magnet.
- By moving the coil into or out of the magnetic field.
- By changing the area of a coil placed in the magnetic field.
- By moving a magnet towards or away from the coil.
Faraday’s Second Law of Electromagnetic Induction:
- It states that, "the induced emf in a coil is equal to the rate of change of flux linkage".
- The flux linkage is the product of the number of turns in the coil and the flux associated with the coil.
- The formula of Faraday’s 2nd law is given by \(E = -N\frac{dϕ }{dt}\)
- Where E is the electromotive force, Φ is the magnetic flux, and N is the number of turns.
Faraday's Law Question 8:
______ states that a current will be induced in a conductor if it is exposed to a changing magnetic field.
Answer (Detailed Solution Below)
Faraday's Law Question 8 Detailed Solution
Concept:
Faraday's first law of electromagnetic induction:
- Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced.
- If the conductor circuit is closed, a current is induced which is called induced current.
Faraday's second law of electromagnetic induction:
- The induced emf in a coil is equal to the rate of change of flux linked with the coil.
\(\Rightarrow e=-N\frac{d\text{ }\!\!\Phi\!\!\text{ }}{dt}\)
Where N = number of turns, dΦ = change in magnetic flux, and e = induced e.m.f.
- The negative sign says that it opposes the change in magnetic flux which is explained by Lenz law.
- According to Faraday's second law of electromagnetic induction, the induced emf in a coil is directly proportional to the rate of change of flux linked with the coil. Therefore option 3 is correct.
- The induced emf in a coil is given as,
Faraday's Law Question 9:
A quantitative relation between induced emf and rate of change of flux linkage is known as
Answer (Detailed Solution Below)
Faraday's Law Question 9 Detailed Solution
Faraday's laws: Faraday performed many experiments and gives some law about electromagnetism.
Faraday's First Law: Whenever a conductor is placed in a varying magnetic field an EMF gets induced across the conductor (called as induced emf), and if the conductor is a closed circuit then induced current flows through it.
A magnetic field can be varied by various methods –
- By moving magnet
- By moving the coil
- By rotating the coil relative to a magnetic field
Faraday's second law of electromagnetic induction states that the magnitude of induced emf is equal to the rate of change of flux linkages with the coil.
- According to Faraday's law of electromagnetic induction, the rate of change of flux linkages is equal to the induced emf
- \(E=N\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right){\rm{Volts}}\)
Where
E = Induced emf
N = Number of turns
\(\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right)\) = Rate of change in flux
Flux linkage:
ψ = N × ϕ
\(E= N\left( {\frac{{{\rm{d\Phi }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
\(E = \left( {\frac{{{\rm{d\Phi N }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
\(E=\left( {\frac{{{\rm{d\psi }}}}{{{\rm{dt}}}}} \right){\rm{}}\)
Faraday’s law of electromagnetic induction, the rate of change of flux linkage is equal to induced emf.
Faraday's Law Question 10:
If the magnetic field vector \(\vec H\) has only z components given by Hz = 3x cos β + 6y sin γ and if the field is invariant with time, the appropriate expression for current density \(\vec J\) is
Answer (Detailed Solution Below)
Faraday's Law Question 10 Detailed Solution
Given, \(H = {H_z} = \left( {3x\cos \beta + 6y\sin \gamma } \right){\vec a_z}\)
\(\nabla \times H = J + \frac{{d\vec D}}{{dt}}\)
Since the field is invariant
∇ × H = J
\(\Rightarrow J = \left| {\begin{array}{*{20}{c}} {{{\vec a}_x}}&{{{\bar a}_y}}&{{{\bar a}_z}}\\ {\frac{\partial }{{\partial x}}}&{\frac{\partial }{{\partial y}}}&{\frac{\partial }{{\partial z}}}\\ 0&0&{3x\cos \beta + 6y\sin \gamma } \end{array}} \right|\)
\(= \frac{\partial }{{\partial y}}\left( {3x\cos \beta + 6y\sin \gamma } \right){a_x} - \frac{\partial }{{\partial x}}\left( {3x\cos \beta + 6y\sin \gamma } \right){\vec a_y} + 0\;{\vec a_z}\)
\(= 6\sin \gamma {\bar a_x} - 3\cos \beta {\bar a_y}\)